Buggy code:
public class CollaborativeRecommender { private static UserBasedRecommender recommender = null ; private static MemoryIDMigrator thing2long = new MemoryIDMigrator ( ) ; private static String rutaReviewInfo = ".//data//reviews_info.txt" ; private static DataModel dataModel = null ; private static GenericBooleanPrefItemBasedRecommender recommenderGBIR ; private static CollaborativeRecommender instance ; public static final int PEARSON = 1 ; public static final int SPEARMAN = 2 ; public static final int EUCLIDEAN = 3 ; public static final long user_id_test = 5 ; private static final String rutaReviewInfoLocationBased = null ; public static void main ( String [ ] args ) { } public static void generateDataModelPositionBased ( ArrayList < Business > businesses ) { try { File data = new File ( CollaborativeRecommender . rutaReviewInfo ) ; Map < Long , List < Preference > > preferecesOfUsers = new HashMap < Long , List < Preference > > ( ) ; BufferedReader br = new BufferedReader ( new FileReader ( data ) ) ; String line ; String negocio_anterior = "" ; boolean contenido_anterior = false ; while ( ( line = br . readLine ( ) ) != null ) { String [ ] parts = line . split ( ";" ) ; String likeName = parts [ 1 ] . trim ( ) ; if ( negocio_anterior . equals ( likeName ) ) { if ( contenido_anterior ) { String person = parts [ 0 ] . trim ( ) ; float preference = Float . parseFloat ( parts [ 2 ] ) ; long userLong = CollaborativeRecommender . thing2long . toLongID ( person ) ; CollaborativeRecommender . thing2long . storeMapping ( userLong , person ) ; long itemLong = CollaborativeRecommender . thing2long . toLongID ( likeName ) ; CollaborativeRecommender . thing2long . storeMapping ( itemLong , likeName ) ; List < Preference > userPrefList ; if ( ( userPrefList = preferecesOfUsers . get ( userLong ) ) == null ) { userPrefList = new ArrayList < Preference > ( ) ; preferecesOfUsers . put ( userLong , userPrefList ) ; } userPrefList . add ( new GenericPreference ( userLong , itemLong , preference ) ) ; System . out . println ( ( ( ( ( ( ( ( ( ( "LocBased<seq2seq4repair_space>" + person ) + "(" ) + userLong ) + ")<seq2seq4repair_space>to<seq2seq4repair_space>" ) + likeName ) + "(" ) + itemLong ) + ")<seq2seq4repair_space>with<seq2seq4repair_space>preference<seq2seq4repair_space>" ) + preference ) ) ; } } else { negocio_anterior = likeName ; if ( CollaborativeRecommender . isContainedIn ( likeName , businesses ) ) { contenido_anterior = true ; String person = parts [ 0 ] . trim ( ) ; float preference = Float . parseFloat ( parts [ 2 ] ) ; long userLong = CollaborativeRecommender . thing2long . toLongID ( person ) ; CollaborativeRecommender . thing2long . storeMapping ( userLong , person ) ; long itemLong = CollaborativeRecommender . thing2long . toLongID ( likeName ) ; CollaborativeRecommender . thing2long . storeMapping ( itemLong , likeName ) ; List < Preference > userPrefList ; if ( ( userPrefList = preferecesOfUsers . get ( userLong ) ) == null ) { userPrefList = new ArrayList < Preference > ( ) ; preferecesOfUsers . put ( userLong , userPrefList ) ; } userPrefList . add ( new GenericPreference ( userLong , itemLong , preference ) ) ; <START_BUG> System . out . println ( ( ( ( ( ( ( ( ( ( "Adding<seq2seq4repair_space>" + person ) + "(" ) + userLong ) + ")<seq2seq4repair_space>to<seq2seq4repair_space>" ) + likeName ) + "(" ) + itemLong ) + ")<seq2seq4repair_space>with<seq2seq4repair_space>preference<seq2seq4repair_space>" ) + preference ) ) ; <END_BUG> } else { contenido_anterior = false ; } } } FastByIDMap < PreferenceArray > preferecesOfUsersFastMap = new FastByIDMap < PreferenceArray > ( ) ; for ( Map . Entry < Long , List < Preference > > entry : preferecesOfUsers . entrySet ( ) ) { preferecesOfUsersFastMap . put ( entry . getKey ( ) , new org . apache . mahout . cf . taste . impl . model . GenericUserPreferenceArray ( entry . getValue ( ) ) ) ; } CollaborativeRecommender . dataModel = new org . apache . mahout . cf . taste . impl . model . GenericDataModel ( preferecesOfUsersFastMap ) ; FileOutputStream fos = new FileOutputStream ( "dataModelLocation.model" ) ; ObjectOutputStream oos = new ObjectOutputStream ( fos ) ; oos . writeObject ( CollaborativeRecommender . dataModel ) ; System . out . println ( "DataModel<seq2seq4repair_space>Generated!" ) ; oos . close ( ) ; } catch ( IOException e ) { System . out . println ( ( ( ( "Exception:<seq2seq4repair_space>" + ( e . getClass ( ) ) ) + ":<seq2seq4repair_space>" ) + ( e . getMessage ( ) ) ) ) ; e . printStackTrace ( ) ; } } private static boolean isContainedIn ( String business_id , ArrayList < Business > businesses ) { } public static void generateDataModel ( ) { } public static ArrayList < Recommendation > executeRecommender ( String userID , int numberOfRecommendations , int neighbors , int similarityMethod ) { } public static List < RecommendedItem > recommendThings ( String user_id , int numberOfRecommendations ) throws TasteException { } public static List < String > booleanRecommendThings ( String user_id , int numberOfRecommendations ) throws TasteException { } public static CollaborativeRecommender getInstance ( ) { } }

Fix:
System . out . println ( ( ( ( ( ( ( ( ( ( "LocBased<seq2seq4repair_space>" + person ) + "(" ) + userLong ) + ")<seq2seq4repair_space>to<seq2seq4repair_space>" ) + likeName ) + "(" ) + itemLong ) + ")<seq2seq4repair_space>with<seq2seq4repair_space>preference<seq2seq4repair_space>" ) + preference ) ) ;